//
// aegis - project change supervisor
// Copyright (C) 1999, 2002, 2005, 2006, 2008, 2011 Peter Miller
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 3 of the License, or (at
// your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
//

#ifndef LIBAEGIS_OUTPUT_FILTER_GZIP_H
#define LIBAEGIS_OUTPUT_FILTER_GZIP_H

#include <common/ac/zlib.h>

#include <libaegis/output/filter.h>

/**
  * The output_filter_gzip class is used to represent an output filter which
  * compresses the data before writing it to the deeper output stream.
  */
class output_filter_gzip:
    public output_filter
{
public:
    /**
      * The destructor.
      */
    virtual ~output_filter_gzip();

    /**
      * The create class method is sued to create new dynamically
      * allocated instances of this class.
      *
      * @param deeper
      *     the output stream this filter will write its output to.
      */
    static pointer create(const output::pointer &deeper);

protected:
    // See base class for documentation.
    long ftell_inner(void) const;

    // See base class for documentation.
    void write_inner(const void *data, size_t length);

    // See base class for documentation.
    nstring type_name(void) const;

    // See base class for documentation.
    void end_of_line_inner(void);

private:
    /**
      * The constructor.  It is private on purpose, use the #create
      * class method instead.
      *
      * @param deeper
      *     the output stream this filter will write its output to.
      */
    output_filter_gzip(const output::pointer &deeper);

    /**
      * The stream instance variable is used to remember somthign that
      * the gzip code wants to remember.  It is opaque to us.
      */
    z_stream stream;

    /**
      * The outbuf instance variable is used to remember the buffered
      * output data.
      */
    Byte *outbuf;

    /**
      * The crc instance variable is used to remember the crc32 of the
      * uncompressed data.
      */
    uLong crc;

    /**
      * The pos instance variable is used to remember the current output
      * position.
      */
    long pos;

    /**
      * The bol instance variable is used to remember whether or not the
      * output is positioned at the beginning of a lone.
      */
    bool bol;

    /**
      * The drop_dead method is used to report a fatal error from the
      * gzip engine.
      */
    void drop_dead(int err);

    void output_long_le(unsigned long x);

    /**
      * The default constructor.  Do not use.
      */
    output_filter_gzip();

    /**
      * The copy constructor.  Do not use.
      */
    output_filter_gzip(const output_filter_gzip &);

    /**
      * The assignment operator.  Do not use.
      */
    output_filter_gzip &operator=(const output_filter_gzip &);
};

#endif // LIBAEGIS_OUTPUT_FILTER_GZIP_H